Simplify the following expression: ${-y-9-6y+6}$
Solution: Rewrite the expression to group the ${y}$ terms and numeric terms: $ {-y - 6y} {-9 + 6}$ Combine the ${y}$ terms: $ {-7y} {-9 + 6}$ Combine the numeric terms: $ {-7y} {-3}$ The simplified expression is $-7y-3$